Brake



y 9 B. H. ANDERSON 1,805,214- 4 BRAKE Filed July 3, 1929 swim doc awnmaga- Tatented May 12, 1931 UNITED STATES PATENT OFFICE :r H. ANDERSON,OF DETROIT, MICHIGAN. ASSIGNOR TO GENERAL MOTORS CORPORATION, OFDETROIT, MICHIGAN, A CORPORATION OF DELAWARE BRAKE Appii cation filedJuly 3, 1929. Serial No. 375,737.

This invention relates to brakes and particularly to vehicle brakes.

An object of the invention is to provide an improvement in the operatingmechanism for the brakes acting to check the rotation of the front andrear wheels. Another object is to provide an automatically variabledifferentiation between the intensity of the braking forces efiective tocheck the rotation of the wheels at the front of the vehicle and at therear. A more specific object is to divide the braking force between thefront and rear wheels in proportion to the rate of deceleration of thevehicle. Other objects will be understood from the followingdescription.

In the drawings: Fig. 1 is a view in perspective of a portion of thevehicle chassis having my improved brake-applying means associatedtherewith. Fig. 2 is a view in side elevation of a part of thebrake-operating mechanism.

Fig. 3 is a section on line 3-3 of Fig. 2. Fig. 4 is a diagrammatic Viewto showthe method of operation.

Referring by reference characters to the drawings, numeral 5 designatesthe longitudinal frame bars of the vehicle; numeral 7 designates thebrake drums. One of these drums is to be used with each of the wheels.Thabrakes within the drums may be of any preferred type andare to beactuated by shafts 9 and 9, these shafts having lever arms 10 and 10respectively. Shaft 9 and arm 10 are shown associated with the rearbrakes and the shaft 9 and the lever 10' are shown associated with thefront brakes. A

pedal 11 is pivoted at 13 to any convenient.

The ends of the rock shaft have oppositely directed arms 21 and 21. Eacharm 21 is connected by a link 23 to one of the rear brakes. Each arm 21'is connected by a link 23' to one of the front brakes. The rock shaft isrotatably journalled at its ends as at in plates 25. These plates arerigidly. secured to arms 27 swingingly supported by pivots 29 carried bybrackets 31 secured to the chassis frame members. It will be seen fromthe drawings that pivots 30 are positioned below pivots 29. By thisconstruction the rock shaft 19 is given a slight forward or rearwardmovement as the arm 27 swings on its pivot 29. Should there be moreclearance Weights represented by numeral 33 are pivoted to the chassisframe member at 35. The weights are so constructed that the center ofgravity is well above the pivot. Links 37 connect the portion oftheweight below pivot with the extreme lower ends of arms 27.

When the vehicle is at rest or travelling at a uniform rate, thereleasing springs associated with the brakes operate to hold the partsin the'position shown on the drawings. Whenthe vehicle is moving forwardand is being decelerated, the inertia weight 33 swings clockwise. Thiscauses a clockwise rotatlon of lever 27 and a consequent movement ofrock shaft 19 slightly to the rear. This results in' a relieving of thetension in the rear rods 23 and in an added pull on rods 23 extending tothe front wheel brakes. The equalized action between the front brakesand the rear brakes is disturbed owing to the movement of rock shaft 19and the brakesatthe front wheels are now more forcibly applied than thebrakes at the rear wheels, the extent of the difference being dependentupon the rate of deceleration. The releasing springs at the brakes arein consequence unequally tensioned and when .the rate of travel is againuniform. they restore the equalizer and the parts connected therewith,including the weight to their initial positions.

It will, of course, be understood that under the influence ofacceleration the weight will also tend to swing, but since when thevehicle is being accelerated the brakes are released. the movement ofthe weight and of shaft 19 even a very light Weight 33 since-itoperatesunder the influence of inertia with a comparat-ively long lever arm.When, as shown in,

Fig. 4 the weight, under influence of inertia, tendsto move in ahorizontal direction, the lever arm, whichis effective to divide'thebraking forces and which is representedby L. will be seen to be ofconsiderable length.

It therefore requires but a small weight to produce the necessarymovement of rock shaft 19 to produce the differentiation in brakingaction required. It may also be well to note that when the vehicle is ona hill the action of gravity is a force tending to rotate the inertiaweight 33 and therefore disturb the position of shaft 19. Thisdisturbing'influence is however negligible as will be seen from aninspection of Fig. 4. In this figure the line designated as W representsthe direction of the pull of gravity and L represents thelever armthrough which this force is actuated. It will be seen that this shortarm L with the small weight will have but little influence in disturbingthe position of rock shaft 19. This figure shows very well, byrepresenting the difference between L and L, that the device is quiteeffective to control the braking action under the influence of inertiabut that the disturb ing influence owing to the inclination of thetherear Wheels.

difi'erence should be in proportion to the rate vehicle may be regardedas negligible.

The above arrangement for brake application is believed to be highlydesirable. If the weight of .the vehicle be distributed with substantialuniformity among the four wheels,

so that each wheel supports an equal load, the brakes should be appliedsubstantially equally to each wheel and, of course, the braking force ateach wheel may be only slightly less than enough to cause wheel locking.When such a vehicle is in motion and the four brakes are applied, thebraking force may be considered as acting below the center of, gravityofthe vehicle in a direction opposite to the direction of travel. I Themass of the vehicle therefore tendsto move forward and as a result theforce applied by the vehicle between the front wheelsand the groundbecomes greater and that between the rear wheels and the form carriesout the inventive idea. It will be understood that in practice theinvention maiy be otherwise embodied.

t will also be understood that the accompanying claims are intended tocover the in? vention as broadly as the state of the art permits.

I claim: 1. In brake operating mechanism, front wheel brakes, rear wheelbrakes, brake operating means, connections between the brake operatingmeans and brakes including a rock shaft, means to support said rockshaft for movement whereby said rock shaft may function to effectequalization between the front brakes and rear brakes, inertia means,connections from said inertia means to said rock shaft supportinmeanswhereby said inertia means may, un er the influence ofdeceleration, move said rock shaft sup orting means a and thereby movesaid rock sha t to unbalance equalization and varythe intensity of brakeaction of the front wheel brakes and rear brakes.

- 2. In brake operating mechanism, front 9 wheel brakes, rear wheelbrakes, brake oper ating means, a rock shaft havinv an arm, a linkconnecting said arm to said brake operating means, arms on said shaft,connections from said arms to said brakes, pivoted swinging supports,said rock shaft being journalled in said supports below the pivots ofsaid sup ports, pivoted weights, connections from said weights to saidsupports.

In testimony whereof I aifix my signature.

BERNARD H. ANDERSON.

ground becomes less. Since the braking.

be evident that after the first act of braking,

wherein the braking force should be substantially equally distributed,the braking force should: be unequally distributed a greater force beingapplied to the front wheels than to It will also be clear that the ofdeceleration. This is precisely what myinvention is designed toaccomplish. I have shown one embodiment which in a simple

